The present invention relates to friction clutches in general, and more particularly to improvements in clutches which are designed to transmit driving torque in machines, apparatus or aggregates wherein the torque fluctuates with a high or very high degree of irregularity and within a wide range. Typical examples of such clutches are compressor clutches for use in automotive vehicles.
German Offenlegungsschrift Pat. No. 29 11 085 discloses a compressor clutch wherein an axially movable pressure plate is biased toward an axially fixed second plate by an annulus of tension springs which bear against the outer marginal portion of the pressure plate and react against a specially designed plate-like retainer. The pressure plate is movable to the disengaged position, against the opposition of tension springs, by an annulus of bolts which extend through the second plate and are movable by a fluid-operated disengaging unit including an axially movable ring acting upon those end portions of the bolts which are remote from the pressure plate.
The just discussed conventional clutch is complex and highly expensive to an extent which is not warranted and/or acceptable in spite of the rather specialized field of application of such types of clutches, namely, in machines or aggregates wherein the driving torque fluctuates extensively and at unpredictable intervals. The complexity of the aforediscussed clutch is attributable, at least in part, to the provision of the aforementioned specially designed retainer as well as to the provision of specially designed cup-shaped receptacles which accommodate the tension springs and extend through the second plate.